Change a demo's nme label or its universe size by clicking on the demo entry in the demo dialog, and then clicking the "Edit" button:

 

 

Make your changes in this "Demo Edit" dialog:

 

 

If you change the name label, it changes only that label, it does not change the definition of the demo.

 

Changing the universe may have an effect on the cost measures.  Any CPP values will be preserved, and CPMs adjusted to fit the new universe.

 

Changing the universe does not affect the reach or frequency of the plan.